1. Field of the Invention
The present invention relates generally to a thermally-zoned substrate holder for maintaining the temperature of the surface of a substrate during processing in a plasma system, and more particularly to a substrate holder including thermal insulation separating multiple temperature controlled zones.
2. Discussion of the Background
It is known in semiconductor manufacturing that processing systems often use and, in many cases, require the incorporation of temperature control elements to control both wall and substrate temperatures and ensure robust substrate processing. For example, temperature control elements can include resistance heaters to heat a substrate holder which supports a semiconductor substrate during a processing step or steps, or to heat the chamber walls in order to reduce residue formation during processing. Moreover, temperature control elements can include fluid channels designed to carry either heated or cooled fluid to and from the substrate holder or chamber wall in order to deposit heat in the processing system or extract heat from the processing system. In general, the substrate temperature as well as the chamber wall temperature, and their respective spatial uniformities, can have a profound influence on the process results.
One example of a substrate holder comprising temperature control elements is shown in FIG. 1. As illustrated in FIG. 1, a substrate holder 11, typically fabricated from aluminum, includes a temperature control element 17, such as a cooling channel or a heating element which generally takes the form of a loop. In some case, heat transfer fins can extend from an internal surface of the temperature control element 17 in the substrate holder 11 in order to effectively increase the wetted surface area through which heat is exchanged between the substrate holder 11 and the temperature control element 17.